This invention relates to improvements in air jet dispersing devices for hogged fuel burning furnaces, and more particularly, to improvements in the means by which combustion air fuel dispersing jet velocity is varied as a function of time in order to improve the time-averaged uniformity of fuel combustion activity over the area of the grate, thereby providing increased efficiency and heating capacity of the furnace. The invention is herein illustratively described by reference to the presently preferred embodiment hereof. However, it will be recognized that certain modifications and changes therein with respect to details may be made without departing from the essential features involved.
The concept of dispersing hogged fuel over the area of a furnace grate using a fan shaped air jet intersecting the path of descent of fuel particles being fed to the fire box in a free fall trajectory is old in the art. Also previously recognized was the advantage to be gained from periodically varying the rate of air flow in the jet. Prior art references of varying degrees of interest and pertinence to the subject generally are as follows (United States Patents):
______________________________________ Patent No. Inventor Issued ______________________________________ 477,387 Scott et al. 6/21/1892 1,311,524 H. G. Lee 7/29/19 1,959,864 O. A. Hartley 5/22/34 2,178,360 G. A. Kohout 10/31/39 2,602,706 Miller et al. 7/8/52 3,137,529 Allen et al. 6/16/64 3,610,182 Richard F. Stockman 10/5/71 3,669,502 Marvin J. Leman 6/13/72 3,812,794 Fred W. Taylor 5/28/74 ______________________________________
The present invention is directed broadly to further improving the efficiency and volumetric capability of hogged fuel burning furnaces. More specifically, it is an object hereof to improve the time-averaged fuel dispersal uniformity over the area of the furnace grate in a manner conducive to maximum combustion efficiency and rate, without unduly complicating the construction, or the criticality of adjustment and operation of the system. A further and related object hereof is to devise an improved air jet fuel dispersal system employing a new and improved technique or mode of combustion air jet velocity modulation.
Still another object hereof is to devise a fuel dispersal system using modulated combustion air velocity that is readily adjustable to suit varying operating conditions, such as heterogeneous fuel particle size, or moisture variance or density (i.e., air dispersability) and combustability. A further and related objective is to achieve more uniform distribution over the fuel bed of large and small particles and dense and light particles making up the heterogeneous fuel.